Display apparatus

ABSTRACT

A display apparatus includes: a display element configured to emit light; a first refractive layer on the display element and having an opening corresponding to the display element; a light extraction pattern located inside the opening of the first refractive layer; and a second refractive layer on the first refractive layer, the second refractive layer covering the first refractive layer and the light extraction pattern.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to and the benefit of Korean PatentApplication No. 10-2019-0050722, filed on Apr. 30, 2019, in the KoreanIntellectual Property Office (KIPO), the entire disclosure of which isincorporated herein by reference.

BACKGROUND 1. Field

One or more embodiments relate to a display apparatus, and moreparticularly, to a display apparatus having excellent luminousefficiency.

2. Description of the Related Art

As the demand for display apparatuses increases, the need for displayapparatuses that may be used for various purposes is also increasing.Display apparatuses tend to become larger or thinner, and the need forlarger or thinner display apparatuses having accurate and clear colorsis also increasing.

SUMMARY

Aspects of embodiments of the present disclosure are directed to adisplay apparatus for improving the efficiency of light extracted in thedisplay apparatus. However, the above aspects are examples and do notlimit the scope of the present disclosure.

Additional aspects will be set forth in part in the description whichfollows and, in part, will be apparent from the description, or may belearned by practice of the presented embodiments.

According to one or more embodiments, a display apparatus includes: adisplay element configured to emit light; a first refractive layer onthe display element and having an opening corresponding to the displayelement; a light extraction pattern located inside the opening of thefirst refractive layer; and a second refractive layer on the firstrefractive layer, the second refractive layer covering the firstrefractive layer and the light extraction pattern.

The display element may include: a pixel electrode; an intermediatelayer on the pixel electrode and including an emission layer; and acounter electrode on the intermediate layer; wherein the firstrefractive layer is on an insulating layer covering an edge of the pixelelectrode.

The display apparatus may further include an encapsulation memberbetween the display element and the first refractive layer.

The display apparatus may further include an input sensing layer betweenthe encapsulation member and the first refractive layer and including asensing electrode.

A refractive index of the second refractive layer may be greater than arefractive index of the first refractive layer.

A refractive index of the light extraction pattern may be equal to arefractive index of the first refractive layer.

The light extraction pattern may be located at a center of the opening,and has the same profile as that of the first refractive layer.

The light extraction pattern may have a closed loop shape that iscontinuous along an edge of the opening.

A plurality of the light extraction patterns may be spaced apart fromone another in the opening.

A height of the light extraction pattern may be equal to a height of thefirst refractive layer.

A height of the light extraction pattern may be less than a height ofthe first refractive layer.

The display element includes a first display element configured to emitlight of a first color and a second display element configured to emitlight of a second color, wherein the light extraction pattern located inthe opening of the first refractive layer corresponding to the firstdisplay element and the light extraction pattern located in the openingof the first refractive layer corresponding to the second displayelement are different from each other in at least one of a shape, asize, and a number.

According to one or more embodiments, a display apparatus includes: adisplay element configured to emit light; a first refractive layer onthe display element, the first refractive layer having a top surfacewith a concave surface corresponding to the display element; a lightextraction pattern on the concave surface of the first refractive layer;and a second refractive layer on the first refractive layer, the secondrefractive layer covering the first refractive layer and the lightextraction pattern.

The display apparatus may further include an encapsulation memberbetween the display element and the first refractive layer.

The display apparatus may further include an input sensing layer betweenthe encapsulation member and the first refractive layer and including asensing electrode.

A refractive index of the second refractive layer may be greater than arefractive index of the first refractive layer.

A refractive index of the light extraction pattern may be equal to arefractive index of the first refractive layer.

A height of a top surface of the light extraction pattern and a heightof a top surface of a non-concave surface of the first refractive layermay be the same.

A height of a top surface of the light extraction pattern may be lessthan a height of a top surface of a non-concave surface of the firstrefractive layer.

The display element may include a first display element configured toemit light of a first color and a second display element configured toemit light of a second color, wherein the light extraction pattern onthe concave surface of the first refractive layer corresponding to thefirst display element and the light extraction pattern on the concavesurface of the first refractive layer corresponding to the seconddisplay element are different from each other in at least one of ashape, a size, and a number.

BRIEF DESCRIPTION OF THE DRAWINGS

These and/or other aspects will become apparent and more readilyappreciated from the following description of the embodiments, taken inconjunction with the accompanying drawings in which:

FIG. 1 is a perspective view illustrating a part of a display apparatusaccording to an embodiment of the present disclosure;

FIG. 2 is a cross-sectional view taken along the line I-I′ of FIG. 1;

FIG. 3 is a view illustrating a part of a display panel according to anembodiment of the present disclosure;

FIGS. 4A and 4B are views illustrating a pixel according to anembodiment of the present disclosure;

FIG. 5 is a partial plan view illustrating an arrangement of pixelsaccording to an embodiment of the present disclosure;

FIG. 6 is a cross-sectional view taken along the line II-II′ of FIG. 5;

FIG. 7 is a partial plan view illustrating a refractive layer accordingto an embodiment of the present disclosure;

FIG. 8 is a cross-sectional view taken along the line III-III′ of FIG.7;

FIG. 9 is a view for describing light extraction of a refractive layeraccording to an embodiment of the present disclosure;

FIG. 10 is a cross-sectional view taken along the line I-I′ of FIG. 1according to an embodiment of the present disclosure;

FIG. 11 is a plan view illustrating an input sensing layer of FIG. 10;

FIG. 12 is a cross-sectional view taken along the line IV-IV′ of FIG.11;

FIG. 13A is a plan view illustrating a first conductive layer of FIG.11;

FIG. 13B is a plan view illustrating a second conductive layer of FIG.11;

FIG. 14 is a partial cross-sectional view of a display panel accordingto an embodiment of the present disclosure;

FIGS. 15-17 are views illustrating a refractive layer according to anembodiment of the present disclosure; and

FIG. 18 is a cross-sectional view of a refractive layer according to anembodiment of the present disclosure.

DETAILED DESCRIPTION

Reference will now be made in more detail to embodiments, examples ofwhich are illustrated in the accompanying drawings, wherein likereference numerals refer to like elements throughout. In this regard,the present embodiments may have different forms and should not beconstrued as being limited to the descriptions set forth herein.Accordingly, the embodiments are merely described below, by referring tothe figures, to explain aspects of the present description. As usedherein, the term “and/or” includes any and all combinations of one ormore of the associated listed items. Expressions such as “at least oneof,” when preceding a list of elements, modify the entire list ofelements and do not modify the individual elements of the list.

While various modifications and embodiments of the present disclosuremay be made, specific embodiments are shown in the drawings and willherein be described in more detail. The features and effects of thepresent disclosure and methods of achieving the features and effectswill be described more fully with reference to the accompanyingdrawings, in which embodiments of the present disclosure are shown.However, the present disclosure is not limited to the embodimentsdescribed below, and may be embodied in various modes.

The present disclosure will now be described more fully with referenceto the accompanying drawings, in which embodiments of the presentdisclosure are shown. Parts in the drawings unrelated to the detaileddescription may be omitted to ensure clarity of the present disclosure,like reference numerals in the drawings denote like elements, and thustheir description may not be repeated.

It will be understood that when a layer, region, or element is referredto as being “formed on” another layer, region, or element, it may bedirectly formed on the other layer, region, or element or may beindirectly formed on the other layer, region, or element withintervening layers, regions, or elements therebetween. Sizes of elementsmay be exaggerated for convenience of explanation. In other words,because sizes and thicknesses of elements in the drawings arearbitrarily illustrated for convenience of explanation, the presentdisclosure is not limited thereto.

It will be understood that when a layer, region, or element is referredto as being “connected”, the layer, region, or element may be directlyconnected or may be indirectly connected with intervening layers,regions, or elements therebetween. For example, when a layer, region, orelement is electrically connected, the layer, region or element may bedirectly electrically connected or may be indirectly electricallyconnected with intervening layers, regions, or elements therebetween.

When a certain embodiment may be implemented differently, a specificprocess order may be different from the described order. For example,two consecutively described processes may be performed substantially atthe same time or may be performed in an order opposite to the describedorder.

It will be understood that although the terms “first”, “second”, etc.may be used herein to describe various elements, these elements shouldnot be limited by these terms, and these elements are only used todistinguish one element from another. As used herein, the singular forms“a”, “an”, and “the” are intended to include the plural forms as well,unless the context clearly indicates otherwise. It will be furtherunderstood that the terms “comprises” and/or “comprising” used hereinspecify the presence of stated components, but do not preclude thepresence or addition of one or more other components.

As used herein, the term “substantially,” “about,” and similar terms areused as terms of approximation and not as terms of degree, and areintended to account for the inherent deviations in measured orcalculated values that would be recognized by those of ordinary skill inthe art.

Also, any numerical range recited herein is intended to include allsub-ranges of the same numerical precision subsumed within the recitedrange. For example, a range of “1.0 to 10.0” is intended to include allsubranges between (and including) the recited minimum value of 1.0 andthe recited maximum value of 10.0, that is, having a minimum value equalto or greater than 1.0 and a maximum value equal to or less than 10.0,such as, for example, 2.4 to 7.6. Any maximum numerical limitationrecited herein is intended to include all lower numerical limitationssubsumed therein and any minimum numerical limitation recited in thisspecification is intended to include all higher numerical limitationssubsumed therein. Accordingly, Applicant reserves the right to amendthis specification, including the claims, to expressly recite anysub-range subsumed within the ranges expressly recited herein.

In the following embodiments, when a wiring “extends in a firstdirection or a second direction”, it may mean that the wiring extendsnot only in a linear shape but also in a zigzag or curved shape in thefirst direction or the second direction.

In the following embodiments, “a plan view of an object” refers to “aview of an object seen from above, and “a cross-sectional view of anobject” refers to “a view of an object vertically cut and seen from theside. In the following embodiments, when elements “overlap”, it may meanthat the elements overlap in a “plan view” and a “cross-sectional view”.

In the following embodiments, a signal collectively refers to a voltageor current unless explicitly specified otherwise. In the followingembodiments, reference symbol C denotes a capacitor and also denotescapacitance that is a size of a capacitor. Also, a directly generatedcapacitor and a naturally generated capacitor are all referred to ascapacitors without discrimination.

FIG. 1 is a perspective view illustrating a part of a display apparatus1 according to an embodiment of the present disclosure. FIG. 2 is across-sectional view taken along the line I-I′ of FIG. 1.

Referring to FIG. 1, the display apparatus 1 according to an embodimentof the present disclosure may include a display area DA and a peripheralarea PA. The peripheral area PA is located outside the display area DAto surround the display area DA. Various wirings and a driving circuitunit for transmitting an electrical signal to be applied to the displayarea DA may be located in the peripheral area PA. The display apparatus1 may provide an image (e.g., a predetermined image) by using lightemitted from a plurality of pixels located in the display area DA. Theperipheral area PA may include a bending area and the display apparatus1 may be bent at the bending area.

The display apparatus 1 may be an organic light-emitting display, aninorganic light-emitting display (or an inorganic electroluminescent(EL) display), or a quantum dot light-emitting display. The followingwill be described assuming that the display apparatus 1 is an organiclight-emitting display. The display apparatus 1 may be any one or moreof various suitable types of electronic devices such as a mobile phone,a notebook, or a smart watch.

As shown in FIG. 2, the display apparatus 1 includes a display panel 10including a substrate 100 and an encapsulation member 300 for sealingthe substrate 100. The substrate 100 and the encapsulation member 300are sequentially stacked in a third direction (e.g., a z-direction).

The substrate 100 may include a glass material or a polymer resin. Forexample, the substrate 100 may include a glass material including SiO₂as a main component, or any one or more of various suitable flexible orbendable materials such as a resin (e.g., reinforced plastic). Theperipheral area PA may include a bending area and the substrate 100 maybe bent at the bending area.

A pixel layer PXL may be located on the substrate 100. The pixel layerPXL may include a display element layer DPL including display elementslocated for each pixel and a pixel circuit layer PCL including a pixelcircuit and insulating layers located for each pixel. The displayelement layer DPL may be located on the pixel circuit layer PCL, and aplurality of insulating layers may be located between a pixel circuitand a display element. Some wirings and insulating layers of the pixelcircuit layer PCL may extend to the peripheral area PA.

The encapsulation member 300 may be a thin-film encapsulation layer. Thethin-film encapsulation layer may include at least one inorganicencapsulation layer and at least one organic encapsulation layer. Whenthe display apparatus 1 includes the substrate 100 including a polymerresin and the encapsulation member 300 that is a thin-film encapsulationlayer including an inorganic encapsulation layer and an organicencapsulation layer, the flexibility of the display apparatus 1 may beimproved.

The display panel 10 may include a refractive layer 400 located on theencapsulation member 300. The refractive layer 400 may adjust a path oflight emitted by a display element of the display element layer DPL andmay function as a lens. The refractive layer 400 may improve lightextraction efficiency at a front surface of the display apparatus 1 bychanging a path of light emitted by a display element, and may improvecolor shift of light emitted to the front surface and light emitted to aside surface.

The display apparatus 1 may further include a polarizer, a window, etc.on the encapsulation member 300 or on the refractive layer 400. Forexample, the refractive layer 400 may be provided between theencapsulation member 300 and the polarizer or between the encapsulationmember 300 and the window.

FIG. 3 is a view illustrating a part of a display panel according to anembodiment of the present disclosure. FIGS. 4A and 4B are viewsillustrating a pixel according to an embodiment of the presentdisclosure.

Referring to FIG. 3, the substrate 100 may include the display area DAand the peripheral area PA. The peripheral area PA may be locatedoutside the display area DA and may surround the display area DA.

A plurality of pixels PX that are arranged in a pattern (e.g., apredetermined pattern) in a first direction (e.g., an x-direction or arow direction) and a second direction (e.g., a y-direction or a columndirection) may be provided on the substrate 100 in the display area DA.

A scan driver 1100 for applying a scan signal to each pixel PX, a datadriver 1200 for applying a data signal to each pixel PX, and main powersupply wirings for applying a first power supply voltage (ELVDD, seeFIGS. 4A and 4B) and a second power supply voltage (ELVSS, see FIGS. 4Aand 4B) may be located on the substrate 100 in the peripheral area PA. Apad unit 140 may be located on the substrate 100 in the peripheral areaPA. The pad unit 140 includes a plurality of signal pads SP where eachsignal pad SP is connected to a data line DL (e.g., a corresponding dataline DL).

The scan driver 1100 may include an oxide semiconductor thin-filmtransistor (TFT) gate driver circuit (OSG) or an amorphous silicon TFTgate driver circuit (ASG). Although the scan driver 1100 is locatedadjacent to a side of the substrate 100 in FIG. 3, the scan driver 1100may be located adjacent to two sides (e.g., two opposite sides) of thesubstrate 100 according to an embodiment.

In FIG. 3, the data driver 1200 is located on a film 1300 electricallyconnected to the signal pads SP located on the substrate 100 by using achip on film (COF) method. According to an embodiment, the data driver1200 may be directly located on the substrate 100 by using a chip onglass (COG) method or a chip on plastic (COP) method. The data driver1200 may be electrically connected to a flexible printed circuit board(FPCB).

Referring to FIG. 4A, the pixel PX includes a pixel circuit PC connectedto a scan line SL and the data line DL and a display element connectedto the pixel circuit PC. The pixel circuit PC may include a transistorand a capacitor, and the display element may include an organiclight-emitting diode (OLED).

The pixel circuit PC may include a first transistor T1, a secondtransistor T2, and a capacitor Cst. Each pixel PX may emit, for example,red, green, blue, or white light, through the OLED. Each of the firsttransistor T1 and the second transistor T2 may be a thin-filmtransistor.

The second transistor T2 that is a switching transistor may be connectedto the scan line SL and the data line DL. The second transistor T2 maytransmit a data signal input from the data line DL to the firsttransistor T1 according to a scan signal input from the scan line SL.The capacitor Cst may be connected to the second transistor T2 and apower supply line PL, and may store a voltage corresponding to adifference between a voltage corresponding to a data signal receivedfrom the second transistor T2 and the first power supply voltage ELVDDsupplied to the power supply line PL.

The first transistor T1 that is a driving transistor may be connected tothe power supply line PL and the capacitor Cst. The first transistor T1may control driving current Ioled flowing through the OLED from thepower supply line PL according to a value of the voltage stored in thecapacitor Cst.

The OLED may emit light having a predetermined (or set) luminance due tothe driving current Ioled. The OLED may include a pixel electrode, acounter electrode, and an emission layer located between the pixelelectrode and the counter electrode. The counter electrode of the OLEDmay receive the second power supply voltage ELVSS.

Although the pixel circuit PC includes two transistors and one capacitorin FIG. 4A, the present disclosure is not limited thereto. The number oftransistors and the number of capacitors may be modified in varioussuitable ways according to the design of the pixel circuit PC.

Referring to FIG. 4B, a plurality of signal lines (e.g., a first scanline SL1, a second scan line SL2, an emission control line EL, and thedata line DL), an initialization voltage line VIL, and the power supplyvoltage line PL are provided for each pixel PX. In an embodiment, atleast one of the first scan line SL1, the second scan line SL2, theemission control line EL, the data line DL, the initialization voltageline VIL, and/or the power supply voltage line PL may be shared byadjacent pixels.

Signal lines include the first scan line SL1 that transmits a first scansignal GW, the second scan line SL2 that transmits a second scan signalGI, the emission control line EL that transmits an emission controlsignal EM, and the data line DL that crosses the first scan line SL1 andtransmits a data signal DATA. The second scan line SL2 may be connectedto the first scan line SL1 of a next row or a previous row, and thesecond scan signal GI may be the first scan signal GW of the next row orthe previous row.

The power supply voltage line PL applies the first power supply voltageELVDD to the first transistor T1, and the initialization voltage lineVIL applies an initialization voltage VINT for initializing the firsttransistor T1 and a pixel electrode to the pixel PX.

A pixel circuit of the pixel PX may include a plurality of transistors(e.g., first through seventh transistors T1 through T7), and thecapacitor Cst. First electrodes E11 through E71 and second electrodesE12 through E72 of FIG. 4B may be source electrodes (source regions) ordrain electrodes (drain regions) according to a type (e.g., a p-type oran n-type) of a transistor and/or an operation condition. The firstthrough seventh transistors T1 through T7 may be TFTs.

The first transistor T1 includes a gate electrode G1 connected to alower electrode CE1 of the capacitor Cst, the first electrode E11connected to the power supply voltage line PL through the fifthtransistor T5, and the second electrode E12 electrically connected tothe pixel electrode of the OLED through the sixth transistor T6. Thefirst transistor T1 functions as a driving transistor, and receives thedata signal DATA according to a switching operation of the secondtransistor T2 and supplies current to the OLED.

The second transistor T2 includes a gate electrode G2 connected to thefirst scan line SL1, a first electrode E21 connected to the data lineDL, and a second electrode E22 connected to the first electrode E11 ofthe first transistor T1. The second transistor T2 is turned on accordingto the first scan signal GW received through the first scan line SL1 andperforms a switching operation of transmitting the data signal DATAtransmitted to the data line DL to the first electrode E11 of the firsttransistor T1.

The third transistor T3 includes a gate electrode G3 connected to thefirst scan line SL1, the first electrode E31 connected to the secondelectrode E12 of the first transistor T1, and the second electrode E32connected to the lower electrode CE1 of the capacitor Cst, the secondelectrode E42 of the fourth transistor T4 and the gate electrode G1 ofthe first transistor T1. The first electrode E31 is connected to thepixel electrode of the OLED through the sixth transistor T6. The thirdtransistor T3 is turned on according to the first scan signal GWreceived through the first scan line SL1 and diode-connects the firsttransistor T1.

The fourth transistor T4 includes a gate electrode G4 connected to thesecond scan line SL2, the first electrode E41 connected to theinitialization voltage line VIL, and the second electrode E42 connectedto the lower electrode CE1 of the capacitor Cst, the second electrodeE32 of the third transistor T3 and the gate electrode G1 of the firsttransistor T1. The fourth transistor T4 is turned on according to thesecond scan signal GI received through the second scan line SL2 andinitializes a gate voltage of the first transistor T1 by transmittingthe initialization voltage VINT to the gate electrode G1 of the firsttransistor T1.

The fifth transistor T5 includes a gate electrode G5 connected to theemission control line EL, the first electrode E51 connected to the powersupply voltage line PL, and the second electrode E52 connected to thefirst electrode E11 of the first transistor T1 and the second electrodeE22 of the second transistor T2.

The sixth transistor T6 includes a gate electrode G6 connected to theemission control line EL, the first electrode E61 connected to thesecond electrode E12 of the first transistor T1 and the first electrodeE31 of the third transistor T3, and the second electrode E62 connectedto the pixel electrode of the OLED.

The fifth transistor T5 and the sixth transistor T6 are concurrently(e.g., simultaneously) turned on according to the emission controlsignal EM received through the emission control line EL so that currentflows through the OLED.

The seventh transistor T7 includes a gate electrode G7 connected to thesecond scan line SL2, the first electrode E71 connected to the secondelectrode E62 of the sixth transistor T6 and the pixel electrode of theOLED, and the second electrode E72 connected to the initializationvoltage line VIL. The seventh transistor T7 is turned on according tothe second scan signal GI received through the second scan line SL2 andinitializes a voltage of the pixel electrode of the OLED. In anembodiment, the seventh transistor T7 may be omitted.

Although the fourth transistor T4 and the seventh transistor T7 areconnected to the second scan line SL2 in FIG. 4B, the present disclosureis not limited thereto. In an embodiment, the fourth transistor T4 isconnected to the second scan line SL2 and the seventh transistor T7 isconnected to other wiring and may operate according to a signaltransmitted to the wiring.

The capacitor Cst includes the lower electrode CE1 connected to the gateelectrode G1 of the first transistor T1 and an upper electrode CE2connected to the power supply voltage line PL. The lower electrode CE1of the capacitor Cst is also connected to the second electrode E32 ofthe third transistor T3 and the second electrode E42 of the fourthtransistor T4.

The OLED includes the pixel electrode, a counter electrode, and anemission layer located between the pixel electrode and the counterelectrode. The counter electrode may receive the second power supplyvoltage ELVSS. The OLED displays an image by receiving the drivingcurrent Ioled from the first transistor T1 and emitting light.

FIG. 5 is a partial plan view illustrating an arrangement of pixelsaccording to an embodiment of the present disclosure. FIG. 6 is across-sectional view taken along the line II-II′ of FIG. 5.

A plurality of pixels located in the display area DA may include a firstpixel PX1, a second pixel PX2, and a third pixel PX3. The first pixelPX1, the second pixel PX2, and the third pixel PX3 may be repeatedlyarranged in a pattern (e.g., a predetermined pattern) in rows andcolumns. Each of the first pixel PX1, the second pixel PX2, and thethird pixel PX3 may include a pixel circuit and the OLED electricallyconnected to the pixel circuit. The OLED of each pixel may be directlylocated on the pixel circuit to overlap the pixel circuit, or may beoffset from the pixel circuit to overlap the pixel circuit of a pixel ofan adjacent row or column. An arrangement of pixels may be anarrangement of the OLEDs of the first pixel PX1, the second pixel PX2,and the third pixel PX3 or an arrangement of pixel electrodes 211 of theOLEDs.

In each of rows R1, R2, . . . , the pixel electrode 211 of the firstpixel PX1, the pixel electrode 211 of the second pixel PX2, and thepixel electrode 211 of the third pixel PX3 may be spaced apart from oneanother and may be alternately arranged in a zigzag pattern. The pixelelectrode 211 of the first pixel PX1 and the pixel electrode 211 of thethird pixel PX3 may be spaced apart from each other and may bealternately arranged on a first imaginary straight line IL1 in the firstdirection (e.g., the x-direction). The pixel electrode 211 of the secondpixel PX2 may be offset in a direction between the first direction(e.g., the x-direction) and the second direction (e.g., the y-direction)from the pixel electrode 211 of the first pixel PX1 and the pixelelectrode 211 of the third pixel PX3. In other words, the pixelelectrode 211 of the second pixel PX2 may be offset from the pixelelectrode 211 of the first pixel PX1 and the pixel electrode 211 of thethird pixel PX3 in the x-direction and the y-direction. The pixelelectrode 211 of the second pixel PX2 may be repeatedly arranged on asecond imaginary straight line IL2 in the first direction (e.g., thex-direction).

In a first column C1, the pixel electrode 211 of the first pixel PX1 andthe pixel electrode 211 of the third pixel PX3 may be spaced apart fromeach other and may be alternately arranged on a third imaginary straightline IL3 in the second direction (e.g., the y-direction). In a secondcolumn C2 adjacent to the first column C1, the pixel electrodes 211 ofthe second pixels PX2 may be spaced apart from each other and may berepeatedly arranged on a fourth imaginary straight line IL4 in thesecond direction (e.g., the y-direction). In a third column C3 adjacentto the second column C2, the pixel electrode 211 of the third pixel PX3and the pixel electrode 211 of the first pixel PX1 may be spaced apartfrom each other in an opposite arrangement to the first column Cl andmay be alternately arranged on a fifth imaginary straight line IL5 inthe second direction (e.g., the y-direction).

The pixel electrode 211 of the first pixel PX1, the pixel electrode 211of the second pixel PX2, and the pixel electrode 211 of the third pixelPX3 may have different areas from each other. In an embodiment, thepixel electrode 211 of the third pixel PX3 may have a larger area thanthat of the pixel electrode 211 of the first pixel PX1 that is adjacentto the third pixel PX3. Also, the pixel electrode 211 of the third pixelPX3 may have a larger area than that of the pixel electrode 211 of thesecond pixel PX2 that is adjacent to the third pixel PX3. The pixelelectrode 211 of the first pixel PX1 may have a larger area than that ofthe pixel electrode 211 of the second pixel PX2 that is adjacent to thefirst pixel PX1. In an embodiment, the pixel electrode 211 of the thirdpixel PX3 may have the same area as that of the pixel electrode 211 ofthe first pixel PX1. The pixel electrode 211 may have a polygonal shapesuch as a quadrangular shape or an octagonal shape, a circular shape, oran elliptical shape, and the polygonal shape may include a shape havinground vertices.

In an embodiment, the first pixel PX1 may be a red pixel that emits redlight, the second pixel PX2 is a blue pixel that emits blue light, andthe third pixel PX3 is a green pixel that emits green light. In anembodiment, the first pixel PX1 may be a red pixel, the second pixel PX2may be a green pixel, and the third pixel PX3 may be a blue pixel.

The display area DA of the substrate 100 may include a first area A1 anda second area A2 around the first area A1. The first area A1 may be anarea where the OLED of each of the first pixel PX1, the second pixelPX2, and the third pixel PX3 is located. The pixel electrode 211 may belocated in the first area A1, and the area of the first area A1 may beless than the area of the pixel electrode 211. The second area A2 (e.g.,a portion of the second area A2) surrounding the first area A1 islocated between a plurality of the first areas A1. A third insulatinglayer 117 may be located in the second area A2. The first area A1corresponds to a portion of the pixel electrode 211 that is exposedthrough a first opening OP1 of the third insulating layer 117, and thesecond area A2 corresponds to a portion where the third insulating layer117 is located between the pixel electrodes 211. Accordingly, the firstarea A1 and the second area A2 of the substrate 100 may correspond tothe first area A1 and the second area A2 of the pixel PX. The first areaA1 is defined as an area corresponding to a bottom surface of the firstopening OP1 having a minimum area when the first opening OP1 is seenfrom above. In FIG. 5, an outline of the bottom surface of the firstopening OP1 is marked by a solid line and an outline of the pixelelectrode 211 is marked by a dashed line.

Referring to FIG. 6, a buffer layer 111 formed to prevent or reducepenetration of impurities into a semiconductor layer of a TFT may belocated on the substrate 100.

The substrate 100 may be formed of any of various suitable materialssuch as a glass material, a metal material, or a plastic material.According to an embodiment, the substrate 100 may be a flexiblesubstrate, and may include a polymer resin such as polyethersulfone(PES), polyarylate (PAR), polyetherimide (PEI), polyethylene naphthalate(PEN), polyethylene terephthalate (PET), polyphenylene sulfide (PPS),polyimide (PI), polycarbonate (PC), or cellulose acetate propionate(CAP).

The buffer layer 111 may include an inorganic insulating material suchas silicon nitride or silicon oxide, and may have a single-layer ormulti-layer structure.

A TFT, the capacitor Cst, and an OLED 200 electrically connected to theTFT may be located on the substrate 100. When the OLED 200 iselectrically connected to the TFT, it may refer to the electricalconnection between the pixel electrode 211 and the TFT (i.e., the pixelelectrode 211 is electrically connected to the TFT). The TFT may be thefirst transistor T1 of FIGS. 4A and 4B.

The TFT may include a semiconductor layer 132, a gate electrode 134, asource electrode 136S, and a drain electrode 136D. The semiconductorlayer 132 may include an oxide semiconductor material. The semiconductorlayer 132 may include amorphous silicon, polysilicon, or an organicsemiconductor material. The gate electrode 134 may have a single-layeror multi-layer structure including at least one of, for example,aluminum (Al), platinum (Pt), palladium (Pd), silver (Ag), magnesium(Mg), gold (Au), nickel (Ni), neodymium (Nd), iridium (Ir), chromium(Cr), lithium (Li), calcium (Ca), molybdenum (Mo), titanium (Ti),tungsten (W), and copper (Cu), in consideration of properties such asadhesion with an adjacent layer, surface flatness of a stacked layer,and processability.

A gate insulating layer 112 including an inorganic material such assilicon oxide, silicon nitride, and/or silicon oxynitride may be locatedbetween the semiconductor layer 132 and the gate electrode 134. A firstinterlayer insulating layer 113 and a second interlayer insulating layer114 including an inorganic material such as silicon oxide, siliconnitride, and/or silicon oxynitride may be located between the gateelectrode 134 and the source electrode 136S and the drain electrode136D. The source electrode 136S and the drain electrode 136D may beconnected to the semiconductor layer 132 through contact holes formed inthe gate insulating layer 112, the first interlayer insulating layer113, and the second interlayer insulating layer 114.

Each of the source electrode 136S and the drain electrode 136D may havea single-layer or multi-layer structure including at least one of Al,Pt, Pd, Ag, Mg, Au, Ni, Nd, Ir, Cr, Li, Ca, Mo, Ti, W, and Cu.

The capacitor Cst includes the lower electrode CE1 and the upperelectrode CE2 overlapping each other with the first interlayerinsulating layer 113 therebetween. The capacitor Cst may overlap theTFT. In FIG. 6, the gate electrode 134 of the TFT is the lower electrodeCE1 of the capacitor Cst. In an embodiment, the capacitor Cst may notoverlap the TFT. The capacitor Cst may be covered by the secondinterlayer insulating layer 114.

A pixel circuit including the TFT and the capacitor Cst may be coveredby a first insulating layer 115 and a second insulating layer 116. Thefirst insulating layer 115 and the second insulating layer 116 may beorganic insulating layers that are planarization insulating layers. Eachof the first insulating layer 115 and the second insulating layer 116may include an organic insulating material such as a general-purposepolymer (e.g., polymethyl methacrylate (PMMA) or polystyrene (PS)), apolymer derivative having a phenol-based group, an acryl-based polymer,an imide-based polymer, an aryl ether-based polymer, an amide-basedpolymer, a fluorine-based polymer, a p-xylene-based polymer, a vinylalcohol-based polymer, or a blend thereof. In an embodiment, each of thefirst insulating layer 115 and the second insulating layer 116 mayinclude PI.

A display element, for example, the OLED 200, may be located on thesecond insulating layer 116. The OLED 200 may include the pixelelectrode 211, an intermediate layer 231, and a counter electrode 251.

The pixel electrode 211 may be located on the second insulating layer116, and may be connected to the TFT through a connection electrode 181on the first insulating layer 115. A wiring 183 such as the data line DLor the power supply line PL may be located on the first insulating layer115.

The pixel electrode 211 may include a conductive oxide such as indiumtin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), indium oxide(In₂O₃), indium gallium oxide (IGO), or aluminum zinc oxide (AZO). In anembodiment, the pixel electrode 211 may include a reflective filmincluding Ag, Mg, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, or a compound thereof.In an embodiment, the pixel electrode 211 may further include a filmformed of ITO, IZO, ZnO, or In₂O₃ over/under the reflective film.

A third insulating layer 117 may be located on the second insulatinglayer 116. The third insulating layer 117 may cover an edge of the pixelelectrode 211, and may be a pixel-defining film that defines a pixel byhaving the first opening OP1 through which a part of the pixel electrode211 is exposed. The first opening OP1 may correspond to the first areaA1. The third insulating layer 117 may increase a distance between theedge of the pixel electrode 211 and the counter electrode 251, therebypreventing or substantially preventing an arc or the like from occurringat the edge of the pixel electrode 211. The third insulating layer 117may be formed of an organic material such as PI or hexamethyldisiloxane(HMDSO).

The intermediate layer 231 includes an emission layer. The emissionlayer may include a high molecular weight material or a low molecularweight material that emits light of a predetermined (or set) color. Inan embodiment, the intermediate layer 231 may include a first functionallayer located under the emission layer and/or a second functional layerlocated over the emission layer. The first functional layer and/or thesecond functional layer may include a layer integrated over theplurality of pixel electrodes 211, or may include a layer patterncorresponding to each of the plurality of pixel electrodes 211.

The first functional layer may have a single-layer or multi-layerstructure. For example, when the first functional layer is formed of ahigh molecular weight material, the first functional layer may include ahole transport layer (HTL) that has a single-layer structure and isformed of poly-(3,4)-ethylene-dihydroxy thiophene (PEDOT) or polyaniline(PANI). When the first functional layer is formed of a low molecularweight material, the first functional layer may include a hole injectionlayer (HIL) and a hole transport layer (HTL).

In an embodiment, the second functional layer may be omitted. Forexample, when each of the first functional layer and the emission layeris formed of a high molecular weight material, it is preferable to formthe second functional layer in order to improve characteristics of theOLED 200. The second functional layer may have a single-layer ormulti-layer structure. The second functional layer may include anelectron transport layer (ETL) and/or an electron injection layer (EIL).

The counter electrode 251 faces the pixel electrode 211 with theintermediate layer 231 therebetween. The counter electrode 251 may beformed of a conductive material having a low work function. For example,the counter electrode 251 may include a (semi)transparent layerincluding Ag, Mg, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, or Ca, or an alloythereof. Alternatively, the counter electrode 251 may further include alayer formed of ITO, IZO, ZnO, or In₂O₃ on the (semi)transparent layerincluding the above material.

The counter electrode 251 may be located on the intermediate layer 231and the third insulating layer 117. The counter electrode 251 may beintegrally formed with the plurality of OLEDs 200 in the display area DAto face the plurality of pixel electrodes 211.

FIG. 7 is a partial plan view illustrating a refractive layer accordingto an embodiment of the present disclosure. FIG. 8 is a cross-sectionalview taken along the line III-III′ of FIG. 7. The same elements as thoseof FIGS. 5 and 6 may not be described.

Referring to FIGS. 7 and 8, a thin-film encapsulation layer may belocated as the encapsulation member 300 on the counter electrode 251.The thin-film encapsulation layer protects the OLED 200 from externalmoisture or oxygen. The thin-film encapsulation layer may have amulti-layer structure. The thin-film encapsulation layer may include afirst inorganic layer 310, an organic layer 320, and a second inorganiclayer 330. Because the thin-film encapsulation layer has a multi-layerstructure, even when cracks occur in the thin-film encapsulation layer,the cracks may be prevented or substantially prevented from connectingto one another between the first inorganic layer 310 and the organiclayer 320 or between the organic layer 320 and the second inorganiclayer 330. Accordingly, the formation of a path through which externalmoisture or oxygen penetrates into the display area DA may be preventedor minimized. In an embodiment, the number of organic layers, the numberof inorganic layers, and an order in which organic layers and inorganiclayers are stacked may be modified.

The first inorganic layer 310 may cover the counter electrode 251 andmay include at least one inorganic insulating layer of aluminum oxide,titanium oxide, tantalum oxide, hafnium oxide, zinc oxide, siliconoxide, silicon nitride, and silicon oxynitride. Because the firstinorganic layer 310 is formed along a structure located under the firstinorganic layer 310, a top surface of the first inorganic layer 310 maynot be flat.

The organic layer 320 may cover the first inorganic layer 310 and mayhave a sufficient thickness. A top surface of the organic layer 320 maybe substantially flat over the display area DA. The organic layer 320may include PET, PEN, PC, PI, polyethylene sulfonate, polyoxymethylene,polyarylate, HMDSO, or an acrylic resin (e.g., PMMA or polyacrylicacid), or a combination thereof.

The second inorganic layer 330 may cover the organic layer 320, and mayinclude at least one inorganic insulating material from among aluminumoxide, titanium oxide, tantalum oxide, hafnium oxide, zinc oxide,silicon oxide, silicon nitride, and silicon oxynitride. The secondinorganic layer 330 may extend to the outside of the organic layer 320and may contact the first inorganic layer 310 in the peripheral area PA,thereby preventing or substantially preventing the organic layer 320from being exposed to the outside.

Structures located under the thin-film encapsulation layer may bedamaged when the thin-film encapsulation layer is formed. For example,when the first inorganic layer 310 is formed, a layer directly under thefirst inorganic layer 310 may be damaged. Accordingly, in order toprevent or reduce damage to a lower structure when the thin-filmencapsulation layer is formed, at least one capping layer and/orprotective layer may be located between the counter electrode 251 andthe thin-film encapsulation layer. The protective layer may include aninorganic material.

A refractive layer 400 may be located on the OLED 200, for example, onthe encapsulation member 300. The refractive layer 400 may adjust a pathof light emitted by the emission layer of the OLED 200 and may functionas a condenser lens. The refractive layer 400 may change a path of lighttraveling in a lateral direction (e.g., a direction other than the thirddirection (e.g., the z-direction)) from among light emitted by theemission layer of the OLED 200 so that the light travels substantiallyforward in the third direction (e.g., the z-direction). The refractivelayer 400 may include a first refractive layer 410 and a secondrefractive layer 430.

The first refractive layer 410 may be located to correspond to thesecond area A2 of the substrate 100, and may have a second opening OP2through which a top surface of the encapsulation member 300corresponding to the first area A1 is exposed. That is, the firstrefractive layer 410 may be formed in a lattice pattern with a pluralityof the second openings OP2. Each of the second openings OP2 of the firstrefractive layer 410 may be formed by patterning a first refractivelayer forming material on the encapsulation member 300 by using aphotoetching process. In FIG. 7, an outline of a bottom surface of thesecond opening OP2 is marked by a solid line, and an outline of a bottomsurface of the first opening OP1 is marked by a dashed line. The secondopening OP2 of the first refractive layer 410 may surround the firstopening OP1 of the third insulating layer 117 and may overlap the firstopening OP1 of the third insulating layer 117. The second opening OP2 ofthe first refractive layer 410 may be equal to or greater in size thanthe first opening OP1 of the third insulating layer 117. A shape of thesecond opening OP2 of the first refractive layer 410 may be the same asthe shape of the first opening OP1 of the third insulating layer 117.Although the second opening OP2 has a quadrangular shape in FIG. 7, inan embodiment, the second opening OP2 may have a circular shape, anelliptical shape, or a polygonal shape such as a triangular shape. Thepolygonal shape may have a shape having round corners.

The first refractive layer 410 may have a first refractive index, forexample, a refractive index of about 1.4 to about 1.5. The firstrefractive layer 410 may include a light-transmitting inorganic materialor organic material having a low refractive index. For example, theinorganic material may include silicon oxide or magnesium fluoride. Theorganic material may include at least one selected from the groupconsisting of PI, polyamide, and tris(8-hydroxyquinolinato)aluminum(Alq3).

The second refractive layer 430 may fill the second opening OP2 of thefirst refractive layer 410 and may be located on the first refractivelayer 410. The second refractive layer 430 may cover an entire surfaceof the substrate 100, and a top surface of the second refractive layer430 may be substantially flat. The second refractive layer 430 may havea second refractive index higher (or greater) than the first refractiveindex of the first refractive layer 410. For example, the secondrefractive layer 430 may have a refractive index of about 1.6 or more,and specifically, a refractive index of 1.6 to 1.8. In an embodiment,the first refractive layer 410 and the second refractive layer 430 mayhave a refractive index difference of 0.1 to 0.3. The second refractivelayer 430 may include a light-transmitting inorganic material or organicmaterial having a high refractive index. For example, the inorganicmaterial may include zinc oxide, titanium oxide, zirconium oxide,niobium oxide, tantalum oxide, tin oxide, nickel oxide, silicon nitride,indium nitride, or gallium nitride. The organic material may include atleast one selected from the group consisting of PEDOT,4,4′-bis[N-(3-methylphenyl)-N-phenylamino]biphenyl (TPD),4,4′,4″-tris[(3-methylphenyl)phenylamino]triphenylamine (m-MTDATA),1,3,5-tris[N,N-bis(2-methylphenyl)-amino]-benzene (o-MTDAB),1,3,5-tris[N,N-bis(3-methylphenyl)-amino]-benzene (m-MTDAB),1,3,5-tris[N,N-bis(4-methylphenyl)-amino]-benzene (p-MTDAB),4,4′-bis[N,N-bis(3-methylphenyl)-amino]-diphenylmethane (BPPM),4,4′-dicarbazolyl-1,1′-biphenyl (CBP),4,4′,4″-tris(N-carbazole)triphenylamine (TCTA),2,2′,2″-(1,3,5-benzenetolyl)tris-[1-phenyl-1H-benzoimidazole] (TPBI),and 3-(4-biphenyl)-4-phenyl-5-t-butylphenyl-1,2,4-triazole (TAZ).

The refractive layer 400 may further include a light extraction pattern450. The light extraction pattern 450 may be located on a path of partof light emitted by the emission layer of the OLED 200. The lightextraction pattern 450 may change a path of part of light of the thirddirection (e.g., the z-direction) incident on the light extractionpattern 450 from among light emitted by the emission layer of the OLED200 so that the light travels in a direction other than the thirddirection (e.g., the z-direction). The light extraction pattern 450 maybe located in the second opening OP2 of the first refractive layer 410,for example, in the first area A1 of the substrate 100. The lightextraction pattern 450 may be provided in an island shape atsubstantially the center of the first area A1. The light extractionpattern 450 may have a third refractive index lower than the secondrefractive index of the second refractive layer 430. In an embodiment,the light extraction pattern 450 may include the same material as thatof the first refractive layer 410, and may include the same refractiveindex as that of the first refractive layer 410. The light extractionpattern 450 and the first refractive layer 410 may be formed by usingseparate processes, or the light extraction pattern 450 may beconcurrently (e.g., simultaneously) formed with the first refractivelayer 410 by patterning a first refractive layer forming material duringthe formation of the first refractive layer 410.

A height H2 of the light extraction pattern 450 may be equal to ordifferent from a height H1 of the first refractive layer 410. Forexample, the height H2 of the light extraction pattern 450 may be lessthan the height H1 of the first refractive layer 410. The term “height”refers to a maximum height of a structure from a top surface of a lowerlayer located under the structure. Width W3 of the light extractionpattern 450 may vary depending on the pixel. For example, the width W3of the light extraction pattern 450 located in the first area A1 of thethird pixel PX3 may be greater than the width W3 of the light extractionpattern 450 located in the first area A1 of the first pixel PX1. Thewidth W3 of the light extraction pattern 450 located in the first areaA1 of the first pixel PX1 may be greater than the width W3 of the lightextraction pattern 450 located in the first area A1 of the second pixelPX2. The term “width” in reference to the width W3 refers to a maximumwidth of the light extraction pattern 450. When a bottom surface of thelight extraction pattern 450 is greater than a top surface of the lightextraction pattern 450, the width may be a maximum width of the bottomsurface of the light extraction pattern 450. Each of the firstrefractive layer 410 surrounding the second opening OP2 and the lightextraction pattern 450 may have a shape whose side surface is linear ortapered and cross-section is quadrangular or trapezoidal. An upperportion of a side surface of each of the part of the first refractivelayer 410 and the light extraction pattern 450 may have a round shape.

The light extraction pattern 450 may include scattering particles. Thescattering particles may be nano-size particles. For example, a particlesize of each of the scattering particles may range from about 50 nm toabout 1000 nm. In an embodiment, the scattering particles may beinorganic particles. For example, the scattering particles may includesilica, ZrO₂, TiO₂, Al₂O₃, In₂O₃, ZnO, SnO₂, and Sb₂O₃. In anembodiment, the scattering particles may be organic particles. Forexample, the scattering particles may include PS, PMMA, acrylic-styrenecopolymer, melamine, or PC. The scattering particles may be one kind ofparticle, or a combination of two or more kinds of particles.

FIG. 9 is a view for describing light extraction of a refractive layeraccording to an embodiment of the present disclosure. FIG. 9 may be apartial enlarged view of FIG. 8.

Referring to FIG. 9, the OLED 200 may be located on an insulatingsurface. The insulating surface may be a top surface of at least oneinsulating layer on the substrate 100. For example, the insulatingsurface may be a top surface of the second insulating layer 116.

A second width W2 of the bottom of the second opening OP2 may be greaterthan a first width W1 of a bottom surface of the first opening OP1. Theterm “width” in reference to the first width W1 and the second width W2refers to a maximum width of a bottom surface. A difference ΔW betweenthe second width W2 and the first width W1 may be different for eachpixel. For example, the difference ΔW between the second width W2 andthe first width W1 at the third pixel PX3 may be greater than thedifference ΔW between the second width W2 and the first width W1 at thefirst pixel PX1, and may be less than the difference ΔW between thesecond width W2 and the first width W1 at the second pixel PX2. Althoughthe second width W2 of the second opening OP2 is the same as a width ofthe pixel electrode 211 in FIG. 9, in an embodiment, the second width W2of the second opening OP2 may be less than the width of the pixelelectrode 211.

In the area OE1 including an inner wall of the second opening OP2 of thefirst refractive layer 410, light L1 incident from the second refractivelayer 430 on the first refractive layer 410 from among light emittedfrom the OLED 200 may be totally reflected at an interface between thesecond refractive layer 430 and the first refractive layer 410 to changea path, and totally reflected light L2 may be extracted in substantiallythe third direction (e.g., the z-direction). Accordingly, the area of alight-emitting pattern of a pixel generated in a front virtual area mayincrease. That is, due to total reflection at an interface between thefirst refractive layer 410 that is a low refractive layer and the secondrefractive layer 430 that is a high refractive layer, forward extractionefficiency may be improved and front visibility may be improved.

In the area OE2 including a side surface of the light extraction pattern450, light L3 incident on the light extraction pattern 450 from amonglight emitted from the OLED 200 may be refracted at an interface betweenthe light extraction pattern 450 and the second refractive layer 430 andrefracted light L4 may be extracted in a direction other than the thirddirection (e.g., the z-direction). Light L5 from among light emittedfrom the OLED 200 may pass through the light extraction pattern 450 andmay be extracted in substantially the third direction (e.g., thez-direction) without changing a direction. Light L6 from among lightemitted from the OLED 200 may pass through the second refractive layer430 without passing through the light extraction pattern 450, and may beextracted in substantially the third direction (e.g., the z-direction)without changing a direction. Although not indicated in FIG. 9, lightincident from the second refractive layer 430 on the light extractionpattern 450 from among light emitted from the OLED 200 may be totallyreflected at an interface between the second refractive layer 430 andthe light extraction pattern 450 to change a path, and totally reflectedlight may be extracted in substantially the third direction (e.g., thez-direction).

When the OLED 200 emits white light, white characteristics observed at afront surface are different from white characteristics observed at aside surface. A white angle difference (WAD) is an item for evaluating achange in white characteristics according to an observation angle, and alevel thereof is evaluated by measuring a luminance change amount and acolor coordinate change amount according to an observation anglecompared with a front surface that is perpendicular to a screen. Thelight extraction pattern 450 according to an embodiment of the presentdisclosure may change a path of light by refracting and/or scatteringpart of light passing through the light extraction pattern 450, therebyreducing a difference between white characteristics observed at a frontsurface and white characteristics observed at a side surface.

FIG. 10 is a cross-sectional view taken along the line I-I′ of FIG. 1according to an embodiment of the present disclosure. FIG. 11 is a planview illustrating an input sensing layer of FIG. 10. FIG. 12 is across-sectional view taken along the line IV-IV′ of FIG. 11. FIG. 13A isa plan view illustrating a first conductive layer of FIG. 11, and FIG.13B is a plan view illustrating a second conductive layer of FIG. 11.FIG. 14 is a partial cross-sectional view of a display panel accordingto an embodiment of the present disclosure. The same elements as thosedescribed above may not be described below.

Referring to FIG. 10, the display apparatus 1 may include a displaypanel 10′ including the substrate 100 and the encapsulation member 300for sealing the substrate 100 which are sequentially stacked in thethird direction (e.g., the z-direction). The display panel 10′ mayfurther include an input sensing layer 500 and the refractive layer 400on the encapsulation member 300. In FIG. 10, for example, the refractivelayer 400 is on the encapsulation member 300 with the input sensinglayer 500 interposed therebetween.

Referring to FIG. 11, the input sensing layer 500 may include a baselayer BL including the display area DA and the peripheral area PA. Thebase layer BL may correspond to the substrate 100 of the display panel10′, and may have substantially the same shape as that of the substrate100. In an embodiment, the base layer BL may be a part of theencapsulation member 300 of the display panel 10′, for example, thesecond inorganic layer 330 (see FIG. 14) located on an uppermost layerof the encapsulation member 300. In an embodiment, the base layer BL maybe an insulating substrate or an insulating film formed of an insulatingmaterial such as glass or a polymer resin separate from theencapsulation member 300.

A plurality of sensing electrodes TSE may be located in the display areaDA. Sensing signal lines connected to the sensing electrodes TSE may belocated in the peripheral area PA. The sensing electrodes TSE mayinclude first sensing electrodes 510 and second sensing electrodes 520.The sensing signal lines may include first sensing signal lines 550A andsecond sensing signal lines 550B. That is, the input sensing layer 500may include the first sensing electrodes 510, the first sensing signallines 550A connected to the first sensing electrodes 510, the secondsensing electrodes 520, and the second sensing signal lines 550Bconnected to the second sensing electrodes 520. The input sensing layer500 may sense an external input by using a mutual capacitance methodand/or a self-capacitance method.

The input sensing layer 500 may include a plurality of conductivelayers. Referring to FIG. 12, the input sensing layer 500 may include afirst conductive layer CML1 and a second conductive layer CML2. A firstinsulating layer 501 as the base layer BL may be located between thefirst conductive layer CML1 and the encapsulation member 300 and asecond insulating layer 503 may be located between the first conductivelayer CML1 and the second conductive layer CML2.

In an embodiment, each of the first and second insulating layers 501 and503 may be an inorganic insulating layer formed of, for example, siliconnitride. In an embodiment, the first insulating layer 501 may be omittedand the first conductive layer CML1 may be directly located on theencapsulation member 300. In an embodiment, each of the first and secondinsulating layers 501 and 503 may be an organic insulating layer.

The first conductive layer CML1 may include first connection electrodes511 as shown in FIG. 13A. The second conductive layer CML2 may includefirst sensing electrodes 510, second sensing electrodes 520, and secondconnection electrodes 521 as shown in FIG. 13B. The second sensingelectrodes 520 may be connected to one another by the second connectionelectrodes 521 that are formed on the same layer as the second sensingelectrodes 520. The first sensing electrodes 510 may be connected to oneanother by the first connection electrodes 511 that are formed on adifferent layer from the first sensing electrodes 510. The firstconnection electrode 511 that electrically connects adjacent firstsensing electrodes 510 may be connected to the adjacent first sensingelectrodes 510 through a contact hole CNT formed in the secondinsulating layer 503.

Each of the first and second conductive layers CML1 and CML2 includes ametal. For example, each of the first and second conductive layers CML1and CML2 may include, for example, Mo, Al, Cu, and/or Ti, and may have asingle-layer or multi-layer structure including the above material. Inan embodiment, each of the first and second conductive layers CML1 andCML2 may have a multi-layer structure formed of Ti/Al/Ti.

Referring to FIG. 13B, the first sensing electrodes 510 and the secondsensing electrodes 520 may have substantially diamond shapes. The firstsensing electrode 510 may have a grid structure (or a lattice structure)having a plurality of holes 510H. The hole 510H may be formed to overlapthe first area A1 of a pixel. Likewise, the second sensing electrode 520may have a grid structure (or a lattice structure) having a plurality ofholes 520H. The hole 520H may be formed to overlap the first area A1 ofa pixel. The holes 510H and 520H may have different sizes. Line widthsof lattice lines may be several micrometers. In FIG. 14, the firstinsulating layer 501 on the encapsulation member 300, the secondinsulating layer 503, and the sensing electrode TSE on the secondinsulating layer 503 are illustrated. The sensing electrode TSE of FIG.14 that is a part of a lattice line of the first sensing electrode 510or the second sensing electrode 520 may be located to correspond to thesecond area A2 of a pixel.

The first sensing electrodes 510 may be arranged in the y-direction, andthe second sensing electrodes 520 may be arranged in the x-directionthat intersects the y-direction. The first sensing electrodes 510arranged in the y-direction may be connected to one another by the firstconnection electrode 511 between adjacent first sensing electrodes 510,to form first sensing lines 510C. The second sensing electrodes 520arranged in the x-direction may be connected to one another by thesecond connection electrodes 521 between adjacent second sensingelectrodes 520, to form second sensing lines 520R. The first sensinglines 510C and the second sensing lines 520R may cross each other. In anembodiment, the first sensing lines 510C and the second sensing lines520R may be perpendicular to each other when viewed in a plan view.

The first sensing lines 510C and the second sensing lines 520R may belocated in the display area DA, and may be connected to a sensing signalpad TP of a pad unit 540 through the first sensing signal lines 550A andthe second sensing signal lines 550B formed in the peripheral area PA.The first sensing lines 510C may be respectively connected to the firstsensing signal lines 550A, and the second sensing lines 520R may berespectively connected to the second sensing signal lines 550B

The first refractive layer 410 may be located on the second insulatinglayer 503. The first refractive layer 410 may cover the sensingelectrode TSE. The light extraction pattern 450 may be located in thesecond opening OP2 of the first refractive layer 410. The secondrefractive layer 430 may be located on the first refractive layer 410and the light extraction pattern 450.

In an embodiment, the display panel 10′ may further include a colorcontrol member such as a color filter between the input sensing layer500 and the refractive layer 400.

In the above embodiments, a profile (shapes of a top surface and a sidesurface) of the first refractive layer 410 and a profile (a shape of aside surface) of the light extraction pattern 450 are the same as orlike each other. In an embodiment, a profile of the light extractionpattern 450 may be different from that of the first refractive layer 410according to an arrangement of pixels and/or emission characteristics ofthe pixels. At least one of a shape and a size of the light extractionpattern 450 and the number (density) and arrangement of the lightextraction patterns 450 in the second opening OP2 may be different foreach pixel according to an arrangement of pixels and/or emissioncharacteristics of the pixels.

FIGS. 15-17 are views illustrating a refractive layer according to anembodiment of the present disclosure. In this case, a plan view PV ofeach of FIGS. 15-17 refers to a top down view of the drawings defined inan x-y plane, and a cross-sectional view CSV refers to a view takenalong the line V-V′ of the plan view PV.

Referring to FIG. 15, the light extraction pattern 450 may be providedin an island shape at substantially the center of the first area A1 ofthe substrate 100. A side surface of the first refractive layer 410surrounding the second opening OP2 may have a linear or tapered shape.The light extraction pattern 450 may have a hemispherical shape whoseside surface is round and cross-section is semicircular. An upperportion of a side surface of the first refractive layer 410 may have around shape. In the plan view PV, an outline of a bottom surface of thelight extraction pattern 450 is marked by a solid line. A width of abottom surface of the light extraction pattern 450 may be different foreach pixel. In FIG. 15, as a size of the pixel electrode 211 increases,a size of the light extraction pattern 450 or a width of a bottomsurface may increase. A height of the light extraction pattern 450 maybe equal to or less than a height of the first refractive layer 410.

Referring to FIG. 16, the light extraction pattern 450 may be spacedapart by a predetermined (or set) interval from a side surface of thefirst refractive layer 410 surrounding the second opening OP2, and mayhave a closed loop shape that makes a continuous round along an edge ofthe second opening OP2. The light extraction pattern 450 may have a lineshape whose cross-section is quadrangular. A side surface of each of thefirst refractive layer 410 surrounding the second opening OP2 and thelight extraction pattern 450 may have a linear or tapered shape. Anupper portion of a side surface of each of the first refractive layer410 surrounding the second opening OP2 and the light extraction pattern450 may have a round shape. In the plan view PV, an outline of a bottomsurface of the light extraction pattern 450 is marked by a solid line. Atotal length of the light extraction pattern 450 may be different foreach pixel. In FIG. 16, as a size of the pixel electrode 211 increases,a total length of the light extraction pattern 450 may increase. Aheight of the light extraction pattern 450 may be equal to or less thana height of the first refractive layer 410.

Referring to FIG. 17, one or more light extraction patterns 450 may beprovided in island shapes at substantially the center of the first areaA1. A side surface of each of the first refractive layer 410 surroundingthe second opening OP2 and the light extraction pattern 450 may have alinear or tapered shape. An upper portion of a side surface of the firstrefractive layer 410 surrounding the second opening OP2 may have a roundshape. In the plan view PV, an outline of a bottom surface of the lightextraction pattern 450 is marked by a solid line. A width of a bottomsurface of the light extraction pattern 450 may be the same for eachpixel, and the number of the light extraction patterns 450 may varydepending on the pixel. For example, in FIG. 17, six light extractionpatterns 450 are provided in the first area A1 of the third pixel PX3,four light extraction patterns 450 are provided in the first area A1 ofthe first pixel PX1, and one light extraction pattern 450 is provided inthe first area A1 of the second pixel PX2. As a size of the pixelelectrode 211 increases, the number of the light extraction patterns 450may increase. A height of the light extraction pattern 450 may be equalto or less than a height of the first refractive layer 410.

FIG. 18 is a cross-sectional view illustrating a refractive layeraccording to an embodiment of the present disclosure.

Referring to FIG. 18, a refractive layer 400′ may include a firstrefractive layer 410′, a second refractive layer 430′, and a lightextraction pattern 450′. In the embodiment of FIG. 18, the firstrefractive layer 410′ has no opening.

The first refractive layer 410′ may be located on the encapsulationmember 300, and may have a concave portion COA that is concave towardthe substrate 100 and a non-concave portion other than the concaveportion COA. The concave portion COA may be a portion corresponding tothe OLED 200. The concave portion COA may be a portion corresponding tothe first area A1 of the substrate 100 or the pixel PX. The non-concaveportion between adjacent concave portions COA may be a portioncorresponding to the second area A2 of the substrate 100 or the pixelPX. A top surface of the concave portion COA of the first refractivelayer 410′ may be concave and a top surface of the non-concave portionof the first refractive layer 410′ may be substantially flat. Athickness (or height) H2′ of the concave portion COA of the firstrefractive layer 410′ may be about ⅖ to ⅗ of a thickness (or height) H1′of the first refractive layer 410′. The thickness H2′ of the concaveportion COA may be a maximum depth of the concave portion COA. Adiameter L of the concave portion COA may vary according to the area ofthe first opening OP1 of the third insulating layer 117.

The second refractive layer 430′ may fill the concave portion COA of thefirst refractive layer 410′ and may be located on the first refractivelayer 410′. Accordingly, the second refractive layer 430′ may have aconvex surface corresponding to the concave portion COA of the firstrefractive layer 410′. The second refractive layer 430′ may cover anentire surface over the substrate 100, and may have a top surface thatis substantially flat. The second refractive layer 430′ may have ahigher (or greater) refractive index than that of the first refractivelayer 410′. The light extraction pattern 450′ may be located between thefirst refractive layer 410′ and the second refractive layer 430′.

The light extraction pattern 450′ may be provided in an island shape atsubstantially the center of a concave surface of the concave portionCOA. The light extraction pattern 450′ may have the same refractiveindex as that of the first refractive layer 410′. The light extractionpattern 450′ and the first refractive layer 410′ may be formed by usingseparate processes, or may be concurrently (e.g., simultaneously) formedso that the light extraction pattern 450′ protrudes from the firstrefractive layer 410′. In FIG. 18, a height of the light extractionpattern 450′ is the same as the thickness H2′ of the concave portion COAof the first refractive layer 410′. In an embodiment, a height of thelight extraction pattern 450′ may be less than the thickness H2′ of theconcave portion COA of the first refractive layer 410′. For example, atop surface of the light extraction pattern 450′ and a top surface of anon-concave surface of the first refractive layer 410′ may be the same,or a top surface of the light extraction pattern 450′ may be less than atop surface of a non-concave surface of the first refractive layer 410′.Although not shown in FIG. 18, the input sensing layer 500 (see FIG. 10)may be further provided between the encapsulation member 300 and therefractive layer 400′.

At least one of a shape and size of the light extraction pattern 450′and the number and arrangement of the light extraction patterns 450′ inthe concave portion COA may be different for each pixel according to anarrangement of pixels and/or emission characteristics of the pixels asdescribed with reference to FIGS. 8 and 15-17.

A display apparatus according to embodiments of the present disclosuremay improve light efficiency extracted at a front surface of the displayapparatus by providing a refractive layer including a low refractivelayer and a high refractive layer. Also, the display apparatus mayimprove color shift of light emitted to a side surface by locating alight extraction pattern that is a patterned structure on a path throughwhich light between the low refractive layer and the high refractivelayer is emitted. Accordingly, when the display apparatus is observed atvarious angles, the display apparatus may form a clear imageirrespective of an observation angle.

The one or more embodiments of the present disclosure may provide adisplay apparatus that may improve efficiency of light extracted in thedisplay apparatus and may emit light having a uniform luminancedistribution even when a user's observation angle changes. However, theabove effects are merely examples, and effects according to theembodiments are described in detail through the description.

It should be understood that embodiments described herein should beconsidered in a descriptive sense only and not for purposes oflimitation. Descriptions of features or aspects within each embodimentshould typically be considered as available for other similar featuresor aspects in other embodiments. While one or more embodiments have beendescribed with reference to the figures, it will be understood by thoseof ordinary skill in the art that various changes in form and detailsmay be made therein without departing from the spirit and scope asdefined by the following claims, and equivalents thereof.

What is claimed is:
 1. A display apparatus comprising: a display elementconfigured to emit light; a first refractive layer on the displayelement and having an opening corresponding to the display element; alight extraction pattern located inside the opening of the firstrefractive layer; and a second refractive layer on the first refractivelayer, the second refractive layer covering the first refractive layerand the light extraction pattern.
 2. The display apparatus of claim 1,wherein the display element comprises: a pixel electrode; anintermediate layer on the pixel electrode and comprising an emissionlayer; and a counter electrode on the intermediate layer, wherein thefirst refractive layer is on an insulating layer covering an edge of thepixel electrode.
 3. The display apparatus of claim 1, further comprisingan encapsulation member between the display element and the firstrefractive layer.
 4. The display apparatus of claim 3, furthercomprising an input sensing layer between the encapsulation member andthe first refractive layer and comprising a sensing electrode.
 5. Thedisplay apparatus of claim 1, wherein a refractive index of the secondrefractive layer is greater than a refractive index of the firstrefractive layer.
 6. The display apparatus of claim 1, wherein arefractive index of the light extraction pattern is equal to arefractive index of the first refractive layer.
 7. The display apparatusof claim 1, wherein the light extraction pattern is located at a centerof the opening, and has the same profile as that of the first refractivelayer surrounding the opening.
 8. The display apparatus of claim 1,wherein the light extraction pattern has a closed loop shape that iscontinuous along an edge of the opening.
 9. The display apparatus ofclaim 1, wherein a plurality of the light extraction patterns are spacedapart from one another in the opening.
 10. The display apparatus ofclaim 1, wherein a height of the light extraction pattern is equal to aheight of the first refractive layer.
 11. The display apparatus of claim1, wherein a height of the light extraction pattern is less than aheight of the first refractive layer.
 12. The display apparatus of claim1, wherein the display element comprises a first display elementconfigured to emit light of a first color and a second display elementconfigured to emit light of a second color, wherein the light extractionpattern located in the opening of the first refractive layercorresponding to the first display element and the light extractionpattern located in the opening of the first refractive layercorresponding to the second display element are different from eachother in at least one of a shape, a size, and a number.
 13. A displayapparatus comprising: a display element configured to emit light; afirst refractive layer on the display element, the first refractivelayer having a top surface with a concave surface corresponding to thedisplay element; a light extraction pattern on the concave surface ofthe first refractive layer; and a second refractive layer on the firstrefractive layer, the second refractive layer covering the firstrefractive layer and the light extraction pattern.
 14. The displayapparatus of claim 13, further comprising an encapsulation memberbetween the display element and the first refractive layer.
 15. Thedisplay apparatus of claim 14, further comprising an input sensing layerbetween the encapsulation member and the first refractive layer andcomprising a sensing electrode.
 16. The display apparatus of claim 13,wherein a refractive index of the second refractive layer is greaterthan a refractive index of the first refractive layer.
 17. The displayapparatus of claim 13, wherein a refractive index of the lightextraction pattern is equal to a refractive index of the firstrefractive layer.
 18. The display apparatus of claim 13, wherein aheight of a top surface of the light extraction pattern and a height ofa top surface of a non-concave surface of the first refractive layer arethe same.
 19. The display apparatus of claim 13, wherein a height of atop surface of the light extraction pattern is less than a height of atop surface of a non-concave surface of the first refractive layer. 20.The display apparatus of claim 13, wherein the display element comprisesa first display element configured to emit light of a first color and asecond display element configured to emit light of a second color,wherein the light extraction pattern on the concave surface of the firstrefractive layer corresponding to the first display element and thelight extraction pattern on the concave surface of the first refractivelayer corresponding to the second display element are different fromeach other in at least one of a shape, a size, and a number.